Precharge Circuit for Capacitors with Different Allowable Currents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicle power supply devices, when capacitors with different capacitances are charged, it takes time to charge the capacitor with larger capacitance due to the need to set voltage according to the allowable current of the capacitor with smaller capacitance.
Innovation Solution
A power supply circuit with a precharge circuit that adjusts precharge current for capacitors with different allowable currents, using a control unit to manage precharge currents such that the first load receives a current equal to or less than its allowable current and the second load receives a current equal to or less than its allowable current, with a maximum current through the second load exceeding the first load's allowable current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage is set according to the allowable current of the capacitor with smaller capacitance, then the capacitor with smaller capacitance can be charged safely, but the charging time of the capacitor with larger capacitance increases
Solution Approach 1:
The precharge circuit dynamically adjusts the precharge current based on which capacitor is being charged. When the first capacitor is charged, the current is limited to the first allowable current. When the second capacitor is charged, the current is increased to the second allowable current, which is larger than the first allowable current. This dynamic adjustment resolves the contradiction by adapting the current level to the specific charging requirement.
Solution Approach 2:
The precharge circuit changes the current parameter based on the charging state. The control unit detects which capacitor is being charged and adjusts the precharge current accordingly. This parameter change allows the system to use higher current for the second capacitor (reducing charging time) while maintaining safe current levels for the first capacitor (ensuring reliability).
Data Source
AI summary
A power supply circuit sets a precharge current flowing through a first load device and a precharge current flowing through a second load device during charging to a first allowable current or less, thereafter sets the precharge current flowing through the first load device to the first allowable current or less, sets the precharge current flowing through the second load device to the second allowable current or less, and sets a maximum value of the precharge current flowing through the second load device to be larger than the first allowable current.